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Full text of "Drafting-room practice"

TJ 

7 
/1 3 



vvy.J u u m. \u 




EACH PAMPHLET IS ONE UNIT IN A COMPLETE LIBRARY OF MACHINE DE- 
SIGN AND SHOP PRACTICE REVISED AND REPUBLISHED FROM MACHINERY 



No. 2 



A Dollar's Worth of Condensed Information 



Drafting-Room Practice 



THIRD EDITION 



Price 25 Cents 



CONTENTS 

Drafting-Room System, by RALPH E. FLANDERS 3 
Tracing, Lettering and Mounting, by I. G. BAYLEY 17 
Card Index Systems, by A. L. VALENTINE, J. S. 



WATTS and A. B. HOWK 



34 



The Industrial Press, 49-55 Lafayette Street, New York 
Publishers of MACHINERY 

COPYRIGHT, 1910, THE INDUSTRIAL PRESS, NEW YORK 



MACHINERY'S 
REFERENCE SERIES 



EACH NUMBER IS ONE UNIT IN A COMPLETE 

LIBRARY OF MACHINE DESIGN AND SHOP 

PRACTICE REVISED AND REPUB- 

LISHED FROM MACHINERY 



NUMBER 2 

DRAFTING-ROOM PRACTICE 

THIRD EDITION 

CONTENTS 

Drafting-Room System, by RALPH E. FLANDERS - 3 
Tracing, Lettering and Mounting, by I. G. BAYLEY 17 

Card Index Systems, by A. L. VALENTINE, J. S. 
WATTS and A. B. HOWK 34 



Copyright, 1910, The Industrial Press. Publishers of MACHINERY, 
49-55 Lafayette Street, New York City 



* a , V ? :/l*J 



CHAPTER I 



DRAFTING-ROOM SYSTEM* 

The drafting-room may be said to bear a double relation to the shop. 
It is the place where designs are originated, and so in a sense it is 
the head of the shop, furnishing it with the ideas which the machinist 
turns into concrete forms in iron and steel. On the other hand, the 
drafting-room may be the servant of the rest of the establishment, 
doing its calculating and its routine work of testing, etc., lessening 
the tax on the memory, and leaving the minds of the workmen and 
foremen free to the task of getting out the product. In different shops, 
the use which is made of these two functions varies one or the other 
of them may be neglected. It is safe to say, however, that there 
are scores of shops where the drafting-room is looked upon as an 
almost unnecessary evil, and every cent which is spent in its salaries 
and supplies begrudged, when this part of the plant might be the serv- 
ant of the whole, making the work go more smoothly and easily all 
along the line, from office to shipping-room, if the men in charge under- 
stood how to get from it its full value. It is this second function which 
is, perhaps, least understood. In the following, attention will be calle'd 
to some of the different ways in which the drafting-room may lighten 
the labors of the workmen, lessen the strain on the foreman, and 
grease the wheels of industry generally. We will neglect entirely the 
matter of design, therefore, and consider the routine office work of a 
typical shop. All the ideas which will follow have been put into 
practical and satisfactory use, some of them for years in the largest 
establishments in the country. 

Systems will vary greatly in such widely varying lines as fire-arms, 
electrical apparatus and milling machines, but in order to take a case 
which will be most suggestive, suppose it is required to equip with 
all necessary drawings, lists and records, a small shop building a line 
of machine tools. 

Numbering the Parts 

We should have to start with a layout of the machine in hand, done 
to accurate scale, made either as a new design or a copy of a machine 
already being produced. The first question to consider is that of num- 
bering the parts and arranging the detail drawings. A good way to 
number the parts, drawings, etc., is to give to each variety of tool 
produced a distinctive letter, such as "A" for universal, "B" for plain, 
and "C" for vertical milling machines, "D" for shaper, and so on. 
Attached to this is a number distinguishing the size. "B2" is No. 2 
plain miller, "L24" might be 24-inch lathe, and so on. The men in the 
shop and office alike soon fall into the way of calling the machines 



* MACHINERY, March, 1905. 



347513 



' *: r ]Vo.'- 2 DRAFTING-ROOM PRACTICE 

by these nicknames. Then each separate part is given a serial num- 
ber. Thus "L20-49" might mean the head cone gear for a 20-inch 
lathe. This designation would be marked on the pattern and serve as 
a pattern number as well. 

The arrangement of the parts in order for numbering depends on 
whether the parts are to be manufactured and fitted in assembling, or 
fitted each to the other in the process of making. We may take it for 
granted that the shop is trying at least to do business in a profitable 
way, so the arrangement will be considered from a manufacturing 
standpoint. The parts should then be grouped in such manner that 
pieces having similar operations involved will be detailed on the 
same sheets. First will come the large castings, like the beds, legs, 
tables, heads, etc.; after, come the other small castings, involving 
milling and drilling mostly, as the brackets, levers, braces, gear guards, 

FULL SHEET - "D" SIZE - 36" X 24" 



H"Size-I8''x W" 


"P" Size 


9"xl2" 


"L" Size - 18" x 12" 



Fig. 1. Standard Size Drawing Sheets 

etc.; then the castings which are finished mostly by turning, like 
pulleys, gears, and bronze bushings. Next comes the group which 
includes the turned parts made from stock or forgings, such as spin- 
dles, shafts, steel gears, etc.; followed by a group of the small parts 
made on the screw machine. The last class contains the parts made 
by milling and drilling from flat and rectangular stock. If the parts 
are numbered and arranged on the drawings in some such order as 
this, the workman who makes a specialty of certain operations will 
have all his work conveniently grouped together on the sheets. 

Standard Drawing- Sizes 

To obtain the greatest simplicity in handling and indexing in the 
drawing office, it is necessary to have a single standard size for the 
sheets. In the shop, however, big blueprints are a nuisance, and the 
sheets should be no larger than is needed to show a convenient num- 
ber of the parts in the group being detailed. It is possible to satisfy 
the requirements of both shop and office by making the tracings of a 



DRAFTING-ROOM SYSTEM 



standard size, and cutting the prints up afterward into as many 
smaller sheets as may be necessary. Fig. 1 shows how the convenient 
36-inch by 24-inch "D" size sheet may be cut up into the other smaller 
sizes; thus it may make two "H" sheets, or four "L" sheets, or eight 
"P" sheets, or two "L" sheets and four "P" sheets, and so on. The 
smaller size is especially suitable for the parts made on the screw 
machine. If an extra large sheet is needed for an assembly, or a full- 
size view of a large casting, a 36-inch by 48-inch sheet, or larger, may 
be made, folded into the standard sheet dimensions, and filed with the 
rest. 

Detailing- 
Starting in the order in which the parts have been grouped, detail 
them out on large sheets, sub-divided to suit the case in hand. Don't 



B-3 LOT 113 - 130 


CHANGES 

2-17-04 R E F 






GEARS IN FEED MECHANISM. 


6-11-04 A.W.B. 
6-17-04 A.W.B. 




i 


N-3 PLAIN MILLING MACHINE. 








SMITH MACHINE Co. 








BOSTON, MASS. 








DRAWN . R.E. M TRACE o AW. B. 
CHECKED. S A. L. DATE JAN. 3, 1904 








B3- 


97-130 












i 



MACHINERY N. Y, 



Fig. 2. Lower Right-hand Corner of Drawing 

try to crowd them, but give plenty of room for changes and additions, 
and leave space in each drawing for adding other parts of a similar 
group, if this should be required in the future The lower right-hand 
corner of each section is ruled off into a title as shown in Fig. 2, con- 
taining on the top line the symbol of the machine, in this case B3, 
which means No. 3 plain miller, then the lot number, which is filled in 
on the print, and lastly, the list of part numbers included on that 
drawing. The second line contains in large letters a title descriptive 
of the contents of that drawing; the next names the machine, and 
after that comes the firm name and the space for initials and dates. 
The column at the right, headed "Changes," will be explained later on. 
In assigning numbers to the parts, leave a few numbers out at the 
start to give to the assembled drawings when they are made. Begin 
by numbering the column, say, No. 15. Leave out two or three num- 
bers, to give leeway, if it is desired to add any new details to that 
sheet later on, and then number the knee and saddle, for instance, if 
they come next, 19 and 20. The first sheet then would include Nos. 
15 to 18, and so 15-18 would be printed in the proper space in the 
top line. The drawing with the knee and saddle, containing only these 



6 



No. 2 DRAFTING-ROOM PRACTICE 



two details might be numbered 19-23, and so on. In the same manner, 
if the first group ends at 60, begin the next group at 100; that might 
end at 271 and the next begin at 300, and so on. Thus parts and draw- 
ing will be numbered in a flexible way which will make additions easy 
without deranging the list of parts. In the margin at the lower right- 
hand corner of the sheets should be placed the numbers inclusive of 
all the details on all the drawings of that sheet, as shown in the sam- 
ple title, Fig. 2. This is for convenience in filing the tracings. 

Dimensioning- 

In detailing, the way in which the parts are dimensioned, the com- 
pleteness of the information given by the dimensions and the notes, 



Buff 




Vie" x /n Koyv-ay 



NO. 71-FEED CHANGE LEVER. 

1-CAST IRON. 



Fig. 3. Detail Drawing 



and the clearness of the drawing itself, all these points together make 
the difference between help and hindrance. Much has been written in 
mechanical papers, and much more said in the shop, profanely and 
otherwise, about the dimensioning of drawings. The draftsman must 
keep in his mind's eye the whole course of the manufacture of the 
piece, and give the dimensions in such manner that the workman will 
not have to add or subtract or multiply or divide this and that to 
obtain the measurement he requires. Of course no scaling of draw- 
ings is allowed in the shop. The ideal to be kept in mind is that of 
a drawing having information so completely given that the wayfaring 
man, though a fool, need not ask questions, but take the blueprint, 
follow it in blind confidence, and turn out work all completed save for 



DRAFTING-ROOM SYSTEM 1 

the little squaring up of shoulders that may be needed in fitting it in 
place in the machine. In Figs. 3 and 4 are shown detail drawings, 
which more or less completely illustrate this idea. 

Fig. 3 shows a cast-iron lever. The handle is not turned, hut buffed, 
as noted. Since the body part has no finish given, it is painted to 
correspond with the rest of the machine. The ends of the hub and 
the face of the boss are marked "/," which means "finish." This idea 
is sometimes carried out more completely by making f 1 , for instance, 
mean a ground surface, f , a filed surface, f , a smooth-turned, but it is 
much less confusing to write out in plain English whatever finish may 
be required other than that left by the cutting tool. Do not be afraid 
of putting on the drawing any notes which will aid the operative. 
"Finish" is often indicated by a red line about 1/16 inch outside of the 
finished surface and parallel with it. This is the best and clearest 
way on paper drawings, and blueprints as well, when the red lines 
print well, but it takes good paper and careful printing. 

The dimension from the center line of the hub to that of the boss 
is marked "about 3 inches." This means that the centralizing of the 
holes in the casting is of more importance than the actual dimension 
given. The hole in the hub is marked %-inch "std.," or "standard," which 
means that it is to be reamed to fit a standard plug gage. The hole 
in the hub is marked "drill," which shows that it is not to be reamed 
or fitted, but left as the drill leaves it. It will be noticed that a "fit" 
of 1/16 inch is indicated at one end of the hub. The workman who 
squares up the casting at this point must leave 1/16 inch for the fitter 
to remove in putting the machine together. In the same way "fit" is 
indicated on the drawings of all shafts, etc., where it is necessary to 
square up a shoulder to make an end fit. This relieves the lathe hand 
of all speculation as to where his fits come. Under the detail are 
placed the part number, the name, the material of which it is to be 
made, and the number wanted for each machine. 

There are no casting or pattern dimensions given in the detail. It 
is an unmitigated nuisance to have the shop drawings obscured by a 
maze of dimensions which are never used but once, when the pattern 
is made. These pattern figures may be placed on the paper drawing 
from which the tracing is taken, or they may be put in with a yellow 
pencil on a blueprint taken specially for that purpose. Of course, when 
it is necessary for a finished surface to bear a definite relation to 
a rough surface, dimension lines may be drawn from that point, but 
otherwise the shop should have to do only with the finished surfaces. 

The detail drawings for the patternmaker should show the draft 
plainly wherever it is required, show the manner in which a finish 
cut terminates in the rough casting, and, in general, give a true pic- 
ture of the piece as it will look when finished in cold metal. This 
relieves the patternmaker of all guesswork as to whether he ought to 
add or take off the draft, and, 'when combined with careful pattern- 
making, furnishes a record of the exact shape of the castings, which 
will be useful in estimating clearances in future changes. 

Fig. 4 shows a sample detail of a steel pinion and shaft. Limits 



No. 2 DRAFTING-ROOM PRACTICE 

are shown for all the diameters. The determination of limits calls 
for good judgment on the part of the draftsman. It is very natural 
for him to put the standard much too high, while the shop often com- 
plains of the closeness called for, not realizing that by the old cut- 
.and-fit method much closer work was done than is needed or called 
for under the limit system. Limits may be expressed in two ways. 
For instance, a running fit on a shaft to go in a 1 14 -inch standard hole 
in a bronze box may be marked 1*4 



or it may be expressed 



0.001 max. 
0.0015 min. 



0.249 
0.2485 



The first way may be best for shops where the workmen have not 
yet become acquainted with their micrometers, but it savors strongly 
of the "% inch plus 1/32 inch less y 2 of 1/64 inch" of our forefathers. 




NO. 497 PINION SHAFT. 

I -MACHINE STEEL. 



INTERMEDIATE PINION SHAFT. 

2-MACHINE STEEL. 



Fig* 4. Another Example of Detail Drawing 

In the better shops of the country the very errand boys learn to use 
the micrometer with ease and skill, so it would seem that the second 
method of marking the size ought not to puzzle the workmen very 
long. In either case the larger dimensions should be on top, to catch 
the eye first. In places where there are no limits given, of course it 
as understood that good, accurate scale measurement will do. 

On the drawing, the tap drill size and the depth of a tapped hole 
are show r n. The two journals are marked "Grind," which means 
"grind to size"; the one into a plainly shown recess, the other, where 
the box does not come within % inch of the shoulder, up to the fillet. 
In general it is intended that the dimensions shall be so arranged that 
the lathe hand will be able to use them as they stand, without bother- 
some calculation. On work niade from the round or rectangular bar, 
finish marks are omitted. If it is desired that the piece be left rough 
at any point, the words "stock size" may be applied to the figures 
describing that dimension. For instance, on a l^-inch cold-rolled 
shaft turned up for a short distance at each end, the central part 
would be dimensioned l^-inch "stock size." This particular piece is 
used twice in the construction of the machine, and in different locali- 
ties, so it is given two names under the same part number. 



DRAFTING-ROOM SYSTEM 9 

Part Lists 

Two lists are required: A list of detailed parts, and a list of stock 
parts. Every single item of a given machine must be recorded some- 
where, either on the blueprints or in the list of screws, washers and 
other sundries taken from the stock-room or purchased outside. A 
page heading for the list of parts in the casting group is shown, upper 
sketch, Fig. 5. The first column gives the part number; then comes 
the name, then the number wanted, the material of which they are 
cast, and lastly, two columns marked "castings ordered" and "order 
filled." These spaces may be conveniently checked by the one who 
orders the castings, and he will thus have a good idea at any time 
of what progress is being made in supplying the needed material. 
This does not, of course, take the place of whatever foundry order 
system may now be in use. The page heading of the parts made from 
the bar and rod are also self-explanatory, the last two columns being 
filled in with the dimensions of the rough stock needed to make each 
piece. It will be remembered that numerous blank spaces were left 



PART 

No 


NAME 


No 

WANTED 


MATL. 


CASTINGS 

OKD'ffD. 


OROEK 
FiiLeo 


115 


2/stM- (Body, 


/ 


C.I. 






116 


%M d<umrt <3iXAl> 


/ 


_C* 






117 












118 












119 


3&Jr(&' e/tcj^ Jjlct/mflAs 


2 


C.I. 






120 


ci&Ml> dfcr^ cMut-mjrtt 


/ 


C.I. 







PART 
No. 



4/2 



NAME 



C.ff.S. 



M.S. 






itfXcrm 



ok' 



Fig. 5. List of Detailed Parts 

in numbering the parts, to give room for future changes. Similar gaps 
should be left in the list of parts. 

The "List of Stock Parts," of which two sample headings are shown, 
Fig. 6, covers everything not otherwise provided for, and gives all the 
information necessary for ordering. Leave plenty of room here, as 
well, for additions and alterations. These lists may be done in ink 
on printed and ruled blanks of thin bond paper, or they may be type- 
written for blueprinting in the following manner: Do the work in a 
good strong manifolding machine with a new black ribbon. A piece 
of carbon paper should be placed in back* of the sheet with the face 
against it. This prints the back of the sheet as well as the front, 
and makes characters heavy enough to make good blueprints. 

If these lists are printed, clipped together in tough paper covers, and 
distributed generally among those who have any use for them, they 
will save a vast amount of useless mental strain. Before a new lot of 
machines is ordered, the stock-keeper can go through the list and see 



10 



No. ^-DRAFTING-ROOM PRACTICE 



that he has got every screw and washer on hand that is needed. The 
man who orders the castings can look over the supply on hand and 
govern himself accordingly. The man who has charge of the bar stock 
can keep himself supplied with the necessary material, and cut it off 
of the proper cross-section to the proper length, as fast as it is needed. 
The foremen in the shop can assure themselves that nothing has been 
forgotten, that everything is coming along as it is wanted, and have 
in general a constant reminder at hand of what is required of them. 

Assembly Views 

After all this has been done, we may make the necessary assembly 
views, working entirely from our detail views and stock part list. 
If the parts all go together as required, it is an indication that the 
job will check up well. On these drawings, at least, and perhaps on 
the details, it is a good plan to use some simple method for distin- 
guishing the various classes of materials by cross-sectioning. It is 

LIST OF Sq HEAD SET SCREWS. 



NAME OF SCREW. 



cfrM&t, &og. # 89 sm, eAoc/t #4/ 



#111 



" vkuvv * 116 *m, 



* 439 



(Reti * 512 



# 54-2 



DlAM. 



* 



L!6TH MAT'L. FINISH POINT 



Steel. 



Steel. 



Steel. 



Iron. 



Iron. 



Z.H 



C.H. 



C.H. 



Soft 



Soft. 



Cup. 



Cup. 



Cup. 



Oval. 



Oval. 



LIST OF FURNISHINGS. 



DESCRIPTION 


AMT PERMACH. J 


Single, Belting made Endless - First Quod. - l-?,'Wicte. 


tiFt.-lln.Endlsss 


Single. Belting - First Quality - 1" Wide'. 


49 Ff-. 


Round Belt - '/4." Diam - Furnished with -Couplings. 


WanM-IIFteach 


"Ccsmoht>ric"0il. 


2i Call's 







Fig. 6. List of Stock Parts 

good enough to have one style for steel and wrought iron, one for 
brass, bearing metals, etc., and one for cast and malleable iron. 

Tracings 

Next comes the tracing. If the machine is a new one, never built 
before, it is a good plan to shellac the paper drawings and send them 
out into the shop for the first lot. This will make the inevitable 
changes easier to handle than when blueprints are used from the start. 
As soon as the machine is well in hand, the drawings may be recalled, 
cleaned with alcohol, and traced. It is of great importance to use the 
very best grade of tracing cloth. Not every well-advertised brand will 
stand the rubbing and scrubbing for a draftsman who has the fever 
of improvement seething in his brain. It costs much less to get the 
best tracing cloth at the start than it does to have to make new trac- 
ings on account of having cloth that will not stand erasure. 

Checking- 

The checking may now be done. It is best to delay this until after 
the tracings are completed, and then it is done once for all; and it 



DRAFTING-ROOM SYSTEM 11 

can best be done by some one other than the man who did the detail- 
ing. If, however, it be gone over in some orderly, systematic way, it 
may be as well done in a one-man drafting-room as in some large 
establishments, where the drawings are examined and initialed by 
every one in sight, from the engineer in charge down to the tracer. 

Think over beforehand every direction in which a mistake is liable 
to occur, and make a table covering these chances of errors and tack it 
in plain sight on the wall over the desk. For such a system as that 
we are considering, the following list might be appropriate: 

1. General design. 

2. Finish. 

3. Dimensions; sufficiency and arrangement. 

4. Dimensions; compared for accuracy. 

5. Compare with list of parts. 

6. Compare with list of stock parts. 

7. Pattern number. 

8. Notes. 

9. General title. 

That is to say, beginning with the first part in the list of detailed 
parts, we would examine it first for points in its general design. 1. Is 
it well proportioned, strong enough, and in general harmony with the 
lines of the rest of the machine? Could it be changed so as to require 
less machining, or to make it cheaper to mold (if a casting)? 2. Is 
there any unnecessary finish, and has the needed finish been properly 
indicated? 3. See that the dimensions are sufficiently full, and 
arranged in such manner that the workman will know, without figur- 
ing, the dimensions he needs. 4. Compare the dimensions of the detail 
in hand with those of every single contiguous and related piece in the 
whole machine, whether detailed or given in the list of stock parts. 
This is the important item in the list, and if it is faithfully carried 
out, it will double-check every dimension, as each part is thus checked 
up once individually, and again in the checking of other related parts. 
5. Compare titles and stock dimensions with entries in the list of 
detailed parts. 6. See that every stock part which is related to the 
detail being considered is properly entered on its list. 7. If the detail 
is a casting which has no pattern of its own, but uses that of some 
other part of the same or another machine, see that the proper pat- 
tern number is given under the title. 8. Be sure that notes are given, 
to supply the workman with all the information he needs as to fit, 
finish, etc. Otherwise he will worry the foreman with fool questions. 
9. After the details have been checked, as above, see to it that the title 
of the drawing is correct as to part numbers, names, etc. 

In the same manner the lists must be gone over, checking every 
name, number, note and dimension. 

Printing 1 , Mounting-, Etc- 

The tracings may now be blueprinted, cut up into the proper sec- 
tions, and mounted on suitable boards. Do not send them out rolled 
up, to get defaced and torn, and refuse to lie flat in the files, when 



12 No. 2 DRAFTING-ROOM PRACTICE 

they are returned. When mounted, they are distributed to whoever 
needs them. With the details intelligently grouped as described above, 
and with not too many on a drawing, one set of detail prints ought to 
suffice to put through a single lot in the shop. Be generous with the 
lists, however, and put them wherever they can be of any service. 
Stamp each print, in red, with the date when it was printed, aria" keep 
a record of prints made and delivered to the shop. This record will 
be found very valuable when making changes as described below. 

Changes 

In a shop which is alive, the product is in constant process of im- 
provement, so it is necessary to make a full provision for this state of 
affairs in a good drafting-room system. In the first place, the men in 
the shop should on no condition be allowed to make an erasure or 
addition of any kind to the shop prints and drawings. If an error is 
discovered or an improvement found advisable, let it be reported at 
once to the draftsman, who should stand ready to make any needed 
change with promptness and good grace. In general practice, however, 
it will be found best, from the drafting-room standpoint and that of 
cheapness of production as well, to delay radical changes until a new 
lot is begun. In some places the foremen and other prominent men 
are furnished with stub books in which they write suggestions for 
the improvement of the different lines of machinery. The leaf is filled 
out in duplicate with the stub, and sent to the drafting-room, where 
it is considered either immediately or when a new lot is ordered, 
according to the urgency of the case. This scheme gives the drafts- 
man the advantage of having all the suggestions in a tangible form, 
for ready reference, and also gives the credit to the men who hold 
the duplicate stubs. 

In the same manner as was done when checking, it will be found 
advisable to make out a list of everything which might require atten- 
tion in making alterations of any kind. The following table would 
cover about everything. This ought also to be printed and nailed on 
the wall in plain sight of the draftsman: 

1. Detail tracings. 

2. Assembly tracings. 

3. List tracings. 

4. All prints (detail, assembly and lists). 

5. Patterns. 

6. Special tools. 

7. Record of changes. 

In making a change, if it is at all elaborate, it is safest to sketch 
it out on detail paper before making changes on the tracing. In eras- 
ing tracings, use any smooth sand eraser which has been approved by 
experience, and place under the part being treated a sheet of some 
smooth hard substance like celluloid, sheet metal, or a round-edged 
piece of glass. This will remove the ink without giving the rubber a 
chance to deeply abrade the cloth itself. Cases sometimes occur in 
which a comparatively simple change, like shortening the over-all 



DRAFTING-ROOM SYSTEM 13 

length of a complicated casting, would entail a considerable amount of 
labor. To avoid this, the dimensions only may be changed, and then 
a small heavy circle drawn around each dimension. If on a paper 
drawing, draw the circle with red ink; if on a tracing, use black ink. 
This gives notice to whomsoever it may concern that the dimensions 
are out of scale, so that the drawing will not measure correctly. Where 
the change is one of 1/32 inch or less, it is not advisable to alter the 
lines of the detail or circle the figures. 

The assembled drawings should be kept up to date if they are to 
serve any purpose at all. In some cases it might be permissible to 
introduce circled dimensions on these tracings as well, where an other- 
wise small change would require much erasing. The lists also must 
be corrected, of course. 

There are two ways of changing the blueprints, where the change is 
so small as to make a new print inadvisable. One way is to use the 
"soda solution" which acts chemically on the paper itself. This gives 
the most permanent results, but requires some skill in handling, as 
the lines do not appear until some time after the liquid has been 
applied. Chinese white, ground in water, can be used like ink, and 
easily removed when desired so easily, in fact, that it is best to shel- 
lac the changed portion of the print to preserve the lines. With either 
method it is best to draw in the new lines first, and then obliterate 
the old ones with a blue pencil, this being the only known method of 
erasing on a blueprint. Be sure that every print of each tracing is 
changed the list of prints charged should take care of this. If new 
copies of a print are required on a change, destroy the old ones; do 
not leave them lying around, to cause trouble. 

Patterns and special tools must be looked up for each individual 
case, and duplicate written orders made out for changes, one to go to 
the toolmaker or patternmaker, and the other to be kept in the office 
as a record until the work is reported finished. 

Referring again to Fig. 2, there is shown at the right of the title a 
column headed "Changes." After each change is completed and 
checked up, the person making the change should enter here his 
initials and the date, in small legible characters. A "Record of 
Changes" book should be kept. Under the date signed in the 
"Changes" column there should be entered a brief description of the 
alterations, giving exact dimensions, and perhaps the reason for them 
as well. A separate book should be kept for each line of machines 
manufactured. By comparing the last change date on a print with 
that on a tracing, it can immediately be determined whether or not 
the print is up to date. By referring to the given date in the "Record 
of Changes," the exact scope of the alteration can be found at any 
time. This will be found a great convenience. 

In cases where an error has been made in the shop on a machine, 
and a deviation from the drawings in that particular case will save 
a large amount of costly labor and material, such change may be made; 
but it must 'be recorded, for convenience in making future repairs and 
attachments. It is the proper thing to number the machines of a 



14 No. 2 DRAFTING-ROOM PRACTICE 

given kind and size serially, beginning, for instance, by numbering the 
first 20-inch lathe built, No. 1, the next one No. 2, and the one hundred 
and seventy-eighth one No. 178, and so on, as long as the machines 
are built. This number should be stamped in a prominent place, and 
attention called to it in the catalogues and other printed matter of the 
firm. A book for a "Record of Machines Shipped" should be kept, 
with a page for each individual machine. This page is numbered with 
the tool's serial number, and contains name of person or firm to whom 
the machine was sold, a record of the inspector's tests, a description of 
any change from the standard drawings used on other machines in the 
same lot, and a record of all attachments furnished, repair parts sent, 
complaints from user, etc. It is easy to see the value of such a record 
as this in furnishing new parts, remedying defects, and estimating the 
values of various designs. 

After each lot of machines has been approved ready to ship, all the 
prints detail, assembly, and lists should be returned to the office. A 
complete set should be taken from them and the duplicates destroyed. 
File this set of blueprints away in a folio the size of the "H" sheet, 
doubling the "D" size to do this. As far as the work done in the 
home shop is concerned, this, with the office book, will furnish a rec- 
ord of each individual machine for all time, no matter whether it goes 
to Klondyke, or stays in the town where it was made. These folios 
should be kept indefinitely. 

Drawings for Jigs and Fixtures 

It is not feasible to try to make the tool drawings of jigs, special 
cutters, etc., on full-size sheet, even though divided, as the standard 
parts are. These should be made on a suitable standard size of a good 
grade of detail paper in a quick, sketchy way, shellaced, and sent into 
the shop. Number these drawings with the symbol and part number 
of the detail for whose manufacture they are used, adding a serial 
number as well. This serial numbering is common to all tools made, 
no matter for what purpose, and is to be given them in the order the 
drawings come from the office. Thus if L 22-75 is the part number for 
the spindle of the No. 4 vertical miller, the finishing taper reamer for 
the hole in the same might be numbered L 22-75-193. If A 4-267 is the 
index worm-wheel for the No. 4 universal miller, and the next tool 
drawing made is a hob for same, it would be numbered A 4-267-194. 
These numbers should be stamped or etched on the different tools as 
soon as they are made. 

A book should be ruled up for a "List of Tools." A sample page 
heading is shown for this in Fig. 7. The tools are entered serially as 
fast as drawn. The first column gives the date when drawn, the main 
part of the page, the description. Next is a space for a list of parts 
for which this tool is used other than the one it was made for. As 
changes are made, old numbers are crossed off from here and new ones 
added, so plenty of space must be allowed. For convenience in finding 
the drawing, the last column gives the standard size of sheet on which 
the tool was drawn. It will be noted that one tool is marked "None." 



DRAFTING-ROOM SYSTEM 



15 



This tool was made in the shop off-hand, without any drawing to go 
by, but it was entered on the list, and its tool number marked on it, to 
give it a local habitation and a name. These tools and jig sheets 
should be filed in a drawer of their own, divided into compartments of 
suitable size, and all arranged with serial numbers in order, the lowest 
at the bottom. The jigs and tools themselves are best arranged with 
the serial numbers in order, since they will avoid constant rearrang- 
ing as the stock increases. To find them readily, an index list should 
be prepared, giving the standard machine parts in numerical order, 
and listing under each one all the special tools used in its production, 
whether those tools were originally used for it or not. Of course much 
of this system of keeping track of special tools is required only in 
shops where they are used in large numbers, but that may be taken 
for granted, if the concern is in earnest about doing a profitable busi- 
ness on a large scale. 

Special Machines and Attachments 

In cases of special machines or outside work of any kind, which does 
not come under the head of standard product, the same system may 



DATE. 



2-17-04 



2-17-04 



2- 10-04 



2-20-04. 



TOOL No. 



H 14-76 -276 



B2- 28-277 



52-28-278 



NAME. 



J-u. 



USED ALSO FOR. 



(H7-96) (Kh72)(L'l4-472) 



(0 2- 49) (H& - 82) (L 17- 24) 



(120- 400} (L24-4&0) 



Non 



MACHINERY N.Y. 



Fig. 7. List of Tools 



be followed as a whole, with the exception of the symbol for the ma- 
chine, which should be given a serial number instead of the letter and 
size number of the regular product. A record of these serial numbers 
should be kept in the office, and the drawings filed away, if the job is 
important, in the same manner as the standard blueprints. Attach- 
ments to regular machines, made up separately, may follow the entire 
system for standard parts. The symbol describing them may be 
formed by adding a letter to the symbol letter of the machine. Thus 
AA-3 would be "Vertical Milling Attachment for No. 3 Universal 
Miller"; BD-4 would be "Rack Cutting Attachment for No. 4 Plain 
Miller," etc. 

In place of the record books suggested, it might be better to use 
loose leaves, with punched holes, held in suitable binders. These 
leaves could then have proper entries made on them on the typewriter, 



16 No. 2 DRAFTING-ROOM PRACTICE 

and thus save hand work. It will be noted that in no case are there 
any forms used in such numbers as to require the use of printed mat- 
ter, so the initial expense is small. Printed forms, index systems, etc., 
may be evolved as the shop grows. 

Summary of Advantages of System Outlined 

In recapitulation, a drawing office managed in some such way as 
this will give the firm the benefit of the following advantages: 

Complete tracings and blueprints, easily filed and indexed, and made 
in such a way as to give the fullest, clearest information possible to 
the workman. 

Complete list of parts as a convenience in tracing the progress of 
the work and keeping up the supply of raw material. 

Complete list of all stock parts, for the benefit of -the assembling 
foreman and the stock-keeper. 

A list of all tools used for any given part, and ready means for find- 
ing the same, also means for ordering duplicate tools by number from 
the original drawings. 

Means for making all changes entailed by changes in the product in 
a simple, comprehensive way, and for making a permanent record of 
same. 

A record of the suggestions made in the shop and office, for the 
drafting-room in making changes, and for the firm in determining the 
relative value of their employes. 

A full individual history, by means of the office record and the filed 
prints, of each machine built, useful in many obvious ways. 

There are many men to whom the suggestions given above will 
seem the veritable A B C of the business; on the other hand, there 
are dozens of places where the suggestion of doing things in some 
such way as this would be considered a dangerous and revolutionary 
proposition. But practically all the work covered by a good system 
has to be done by someone, some time, and if it is not done decently 
and in order, it will be done in vexation of spirit, and with waste of 
time and money. 



CHAPTER II 



TRACING, LETTERING AND MOUNTING * 

While the previous chapter has dealt with the system of the drafting- 
room in its relation to the shop, and outlined its functions in a gen- 
eral, although comprehensive, manner, the present chapter is intended 
to deal with the small details of performing the work in the drafting- 
room, at the same time as many valuable hints are included with spe- 
cial reference to the young draftsman. In fact, the present chapter 
has, in particular, been addressed. to the beginner, although it has 
general application. 

At the commencement of a drawing-office career only a few tools 
may be purchased, adding others as they are needed. Careful selec- 
tion is necessary, and good instruments pay for themselves in the end. 
A set of drawing instruments comprising a straight pen or two one 
for black and one for red ink a spring-bow pen, bow pencil, and divid- 
ers, a six-inch compass with fixed needle-points and interchangeable 
pen, pencil, and lengthening bar, will suffice. T-square, triangles, pen- 
cils, rubbers, erasers, and pens are usually provided by the office. Each 
man should keep his own instruments, and have a private mark on 
his triangles, scales and T-square for identification in case they become 
exchanged. 

Small instruments should be put away each night, as in cleaning up 
the office they are easily lost. A drawer or cupboard with trays or 
boxes for the various tools is very necessary for the draftsman. A 
large clean rag duster or brush to wipe the board and T-square occa- 
sionally should be provided, as the least particle of dust getting into 
the pen will clog the ink, causing a poor line to be drawn. In case 
the eraser must be used (a thing to avoid as much as possible) rub 
a little French chalk or soapstone well into the part erased. A little 
of this prepared chalk should always be kept on hand; it can be pro- 
cured from any artists' material store. A piece of rag, cheesecloth 
or chamois skin hung by a thumb-tack at the end of the drawing board 
comes in handy for wiping the pens. A sand-paper pencil sharpener 
and an oil stone completes the list. 

Inks 

Too much cannot be said about the inks used, as I believe to a cer- 
tain extent a great many bad tracings can be laid to the bad quality 
of ink used in the various drawing offices visited by the author, fn 
this country and abroad. 

Good ink is indispensable, and no one should attempt to make a 
tracing until he has it. Some offices, to save (?) expense, resort to 
many ingenious ways of making ink by wholesale. A large bottle 

* MACHIXFRY, September, October, November, 1906. 



18 No. 2 DRAFTING-ROOM PRACTICE 

with a ground-glass stopper is provided. A quantity of broken ink 
(which can be purchased by the pound and much cheaper than buying 
by the stick or cake) is put into the bottle; a quart or so of ammonia 
is then poured over the ink. The bottle is then put in a warm place, 
shaken every now and then until the ink is dissolved, or partly so (the 
latter usually being the case) when it is supposed to be ready for use. 
This is the cheapest and worst way of making ink. Some drawing 
offices buy the ink ready mixed, put up in pint or quart bottles. For 
shop tracings, either of these methods may be resorted to. But for 
neat work it is almost impossible to get along with either; the only 
way is to mix the ink fresh each morning, washing out the pallet 
every day. When purchasing the ink stick, the very best should be 
bought; it can be recognized by a pleasant odor which cannot be mis- 
taken and is perceptible when grinding it in the saucer. The saucer, 
or pallet, should be spotlessly clean, and the water clear. Do not 
use too much water at first; more can be added as the ink is mixed. 
A little vinegar in the ink will keep away the flies. In many offices 
in warm climates they are a great nuisance; the writer has seen whole 
views completely eaten away by these pests in a very short time. 
Commence by rubbing a little Prussian blue in the saucer; this is not 
absolutely necessary, but it improves the ink somewhat and helps to 
thicken it quicker. Saucers made of slate with ground-glass covers 
are the best. The ink stick should be held firmly, but do not bear too 
hard upon it while grinding, or else, when mixed, the ink will be 
gritty. Grind until the bottom of the saucer cannot be seen when 
blowing down into the ink; this is a good test, and one can also see if 
the ink looks gritty. Try it on the edge of the tracing cloth or paper 
to see if it gives a clear black line. The cover should always be kept 
over the ink to keep it from evaporating and free from dust. In cold 
weather, if the ink should thicken, hold it before the fire or heater, 
when it will run easily and will not clog the pen. 

Ordinary scarlet ink is used by. some draftsmen for making red lines, 
although it is much better to use a mixed ink of crimson lake color, 
adding a little ox-gall to make it run. The prepared ox-gall in tiny 
jars can be procured from artists' material stores. In the absence of 
this, a little soap rubbed into the color will answer the purpose. Bi- 
chromate of potash dissolved in the water before mixing the ink will 
help to keep away flies. 

It sometimes happens that draftsmen are troubled with sweaty hands 
which mark the tracing as the work proceeds. This can be avoided 
by putting half a teaspoonful of ammonia in the water used for wash- 
mg the hands. 

Truing- up the Instruments 

As the pens are constantly used they will become blunt, which can 
be seen by holding them against the light and looking down upon the 
nibs. Every draftsman should be able to set his own instruments. 
There should be an oil stone in every office for this purpose. Let it 
lie flat on the window sill or a table near to the light. Screw up the 



TRACING, LETTERING AND MOUNTING 19 

nibs tight, and, holding the pen in an upright position between the 
finger and thumb, move it backward and forward, as shown in Fig. 8, 
along the stone as indicated by the arrows, tilting it from side to side 
as shown by the dotted lines. 

In this way a round and even surface is given to the nibs. They 
will be of the same length and true with each other. Now, holding 
the pen in a slanting position of about 30 degrees, rub the nibs upon 
the stone in a circular direction, as indicated in Fig. 9, rolling the p6n 
as it were between the thumb and finger, turning it over and grinding 
both nibs alike. Hold the pen to the light occasionally to see if the 
nibs are level, and look down upon the points to see if the flat sur- 




Fig 9. 



Fig.8 



Figs. 8 and 9. Truing the Point of the Pen 

faces have been taken out. If sharpened correctly, one will not be 
able to see anything, the same as when looking down upon the edge 
of a razor. 

The thumbscrew must now be taken out and the inside edge of the 
pen be rubbed across the oil stone several times. Thoroughly clean 
the pen from any grit or oil and try it upon the edge of the tracing. 
If too sharp, it will have a tendency to run away from the T-square 
or straight-edge, in which case it should be rubbed on the stone again, 
as in Fig. 8, though with care, as all pens should be fairly sharp. The 
bow pen is trued up in the same way, with the exception that a thin 
slip of stone is passed between the nibs to take off any rough parts, 
as the nibs of the bow pen do not hinge; and when straight pens are 
made in the same way, they should also be treated in the same man- 
ner. All instruments should have the best of care. When not in use 
for some time they should be kept clean and free from rust by wiping 
them on a piece of chamois leather greased with vaseline. 



20 No. 2 DRAFTING-ROOM PRACTICE 

Tracing- Paper 

Tracing paper is much used in architects' offices and occasionally 
by engineers for pencil sketching. When it is used for permanent 
work, the best quality should be had. But although it is possible to 
purchase paper capable of standing fairly rough usage, it is by no 
means as good as cloth. 

A narrow strip of tracing cloth tacked along the lower edge protects 
the paper from being torn while leaning over the board. Either 
thumb-tacks, copper tacks, or small carpet tacks may be used to hold 
down the paper; a small magnetized hammer can be used for the lat- 
ter, picking the tacks up very quickly, so that whichever plan is 
adopted, it takes about the same time. In case the tracing will be 
worked on for some time, or if there is any coloring to be done, the 
paper must be mounted on the board as described later. 

Tracing Cloth 

For permanent work tracing cloth should by all means be used. 
Cloth is either glazed or unglazed, the foreign make being by far the 
best. With proper care a tracing may be taken up when complete, 
as clean as when cut from the roll. All shop or working tracings 
should be made on the unglazed or dull side of the cloth, as this side 
will take pencil lines nicely, and when erasing has to be done it will 
not mar the surface so perceptibly. But for show or estimate trac- 
ings, where much finer and neater work is required, the glazed side 
must be used. The lines will be sharper, and the work will stand out 
much better. Tn either case the cloth should be laid down in the same 
manner as the paper. It should then be rubbed down with pulverized 
chalk. 

Laying- Down the Tracing- 

The drawing to be traced is squared up with the board and wiped 
down with a dry cloth or duster. The roll of tracing cloth is run 
down the board and cut off to correct size. The edges at either side 
are then torn off quickly and the cloth is laid down correct side up. 
A tack is put in the center of the top edge; the flat of the hand is 
drawn firmly but gently down to an opposite point at the lower edge, 
the fingers spread apart, while another tack driven between them 
holds that edge. Run the flat of the hand gently to the one side, driv- 
ing in a tack; then to the opposite, stretching it well and securing it 
by another tack. The four corners and all intermediate spaces are 
then held down in the same manner. 

With a dry rag or piece of chamois skin rub some pulverized chalk 
(or chalk scraped from the stick) all over the tracing cloth, dusting it 
off with a dry rag or brush. This will cause the pen to bite much 
better, especially in the case of show tracings where the glazed side 
is used. Some draftsmen use a little ox-gall in their ink for this pur- 
pose, but unless the exact quantity is used, the ink will be very sensi- 
tive. 

Tracing 

Everything is now ready for tracing. Try to understand the work 
as you proceed. If tb-e job is likely to last long, work on one view 



TRACING, LETTERING AND MOUNTING 



21 



and complete it, as sometimes the temperature of a room will change 
over night, causing the cloth to become quite flabby, and although it 
may be stretched again by holding it near the radiator or in the sun, 
yet it very seldom goes back to its correct position. But when mak- 
ing a smaller tracing which can be completed in a day, put in all the 
black lines first, the red or blue lines next (when making show trac- 
ings), the printing or lettering next, and finally the border and cut- 
ting-off lines. Although as a rule red and blue lines are put in last, 
there are a few exceptions, as, for instance, when tracing a num- 
ber of bolt or rivet heads in bridge or girder work; if a red line is run 




Fig. 10. 



Figs. 1O, 11 and 12. Horn Center, and Examples of Shading 

right through the heads, it will be easier to get them all exactly true 
and In line; otherwise they are apt to be put in a very zig-zag way. 

If the drawing is crowded, the best plan is to stick to the rule and 
put red lines in last, as otherwise they will make the drawing hard to 
read by covering up work not yet traced. As a general rule, com- 
mence with the circles and curves first, joining the straight lines onto 
the curves, and not vice versa. When a number of circles and curves 
are struck from the same center, always commence with the smallest 
or inner one first, while the center is good. 

Sometimes a horn center, shown in Fig. 10, is used to protect centers 
from which a number of curves or circles are struck, as in gear wheels, 
for instance. These horn centers are circular pieces of horn with three 
needle points. Some draftsmen glue a small piece of hard wood or 
horn over the centers. The pens should be tried upon the edge of the 
tracing to see what thickness of line they make, and when once set 



22 No. 2 DRAFTING-ROOM PRACTICE 

they should not be moved; for this reason some pens have small lock 
nuts on the thumbscrews. They should be wiped and the ink put 
in without again adjusting the screw. This particularly applies when 
making heavy lines. In this way all lines will be of the proper thick- 
ness. The pens can be filled with an ordinary writing pen or dipped 

in the ink sideways. 

Working Tracings 

Working tracings or shop tracings are usually made a little heavier 
than others. The lines should be all of the same thickness. No red 
or blue lines need be used, but all black, and although the tracings 
should be neat, especial care being given to the figures and dimension 
lines, yet such care need not be taken as when making a show or esti- 
mate tracing. The figures should be plain and simple and might be 
made a little large. The arrow points should be true and go exactly to 
their intended position. The figures should be checked before hand- 
ing in the tracing so that as few mistakes as possible will come back 

to the tracer. 

Show Tracings 

Estimate or show tracings should have a little more time expended 
upon them. The lines need not be so heavy and as a general rule are 
shaded, i. e., the lines furthest from the light, which is supposed to 
come from the top left-hand corner, should be heavier than the others; 
this is clearly shown in Fig. 12. Shade lines can be made by going 
over the lines again or adjusting the screw of the pen, causing the ink 
to make a heavier line. When dark-lining a circle the radius is kept, 
but the center changed slightly, as shown in Fig. 11; or the same 
center and radius may be kept, going over the dark or shaded side sev- 
eral times with the pen. 

The letters, figures and dimension lines should be made neatly, the 
arrow points evenly made. Some draftsmen put in the arrow heads 
with their spring bow pen, and since they can be put in just as quickly 
this way and look much neater it would be well to practice this method. 
Dotted lines should be finer than full ones. The dots and spaces 
should be made the same length about one-thirty-second to one-six- 
teenth inch in length. In shading rivet heads sometimes a small half 
circle is made inside the first, as shown in Fig. 12. It should be 
heavier than the outline of the rivet head. 

The heading or title should be neat and attractive and a fancy bor- 
der line might be made. All notes or stray words should have a neat 
red line drawn under them. Bolt heads should be neatly made and 
all small work carefully executed. Threads of bolts should be parallel 
and equally spaced, and may be accurately drawn or indicated, as 
shown in Fig. 13, c, d and e. Dotted work can be shown to advan- 
tage if the dots forming the apex and root of the threads are united, 
as shown at e. These may seem trifles, but they all tend to make a 

neat tracing. 

Holding the Instruments 

The author has been more than surprised at the rough and unsteady 
way which some draftsmen have of holding their instruments. The 



TRACING, LETTERING AND MOUNTING 



23 



bow pen should be held lightly at the top between the thumb and first 
two fingers, resting the little finger upon the tracings to steady the 
instrument while finding the position for the point. This being found, 
the little finger should be lifted and the bow pen cleverly spun between 
the thumb and first finger. It is good practice when at leisure to see 
how quickly one can make a number of small circles; in this way 
one will get into the knack of cleverly spinning the bow pen as de- 
scribed, instead of holding it in an awkward manner. The straight 
pen should be held in a slightly inclined position, the thumb-screw on 
the side away from the T-square or straight-edge, and with the sec- 
ond finger resting upon the screw to adjust if necessary. 

Sectioning- 

Sections are shown in several ways. For working tracings line sec- 
tioning is by far the better. Plates and sections in wrought iron or 







Pig. 13. Screw Threads and Shading 

steel work may be blackened, as shown in Fig. 23. A narrow white 
space should be left between two pieces, as shown in Fig. 21. 

A pretty way of showing sections, especially in the case of show 
tracings, is to represent the various metals, wood, etc., by broken and 
full lines, as shown in Fig. 14. These conventions are in common use, 
but in case there should be any doubt as to whether they will be 
generally understood it would be well to make a small note to on_ 
side, naming the material. 

A neat little tool for section lining is easily made from a slip of 
wood a little thicker than the triangle or set square used by the drafts- 
man, as illustrated in Fig. 15. The notch cut in one side is a little 
longer than the side of the triangle. Resting the thumb upon the 
T-square, the first finger upon the sectioner and the second finger 
(all of the left hand) upon the triangle, they are alternately slipped 
along each time a line is drawn with the pen. With a little practice, 
sectioning can be done quicker than by using a triangle and T-square 



24 



No. 2 DRAFTING-ROOM PRACTICE 



only, trusting to the eye for correct spacing. Section lining done this 
way looks very neat and even. Another section liner, shown in Fig. 
16, can be made to fit triangles having a recess in the center. 

Views in section are sometimes colored, generally on the back, turn- 
ing the tracing over and tacking it down again; or, where there is 
much coloring to be done, the tracing should be mounted as described 
under that head at the end of this chapter; otherwise the color will 







(7/7&T //PG/V. 







&/7SBS7T 





LEAD 




WOOD. - 



Fig. 14. Cross-sectioning 



cause the tracing to buckle, giving it a very untidy appearance. Hav- 
ing stretched the tracing, one may be mixing the colors while it thor- 
oughly dries. The colors should be rather thin, and to make them run 
evenly a little prepared ox-gall should be mixed in well with them. 
This should not be omitted, as otherwise the colors will present a very 
smudgy appearance. Some draftsmen use a small piece of soap in 
place of the ox-gall. 

By trying the colors upon a scrap piece of tracing cloth or paper 
and turning it over, the proper shade may be obtained. 



* There is no universally adopted standard for cross-sectioning for the purpose 
of indicating different materials. The chart above does not agree fully with 
the charts given in any of a number of text-books on mechanical drawing, but 
as these at the same time do not agree with one another it has been assumed 
that the chart above represents as good practice as those in the text-books. A 
chart, similar to this, but differing in a few instances, and more extensive, was 
given in MACHINERY'S Data Sheet No. 15, December. 1902. There being no 
recognized standard, however, cross-sectioning alone should never be depended 
upon for indicating materials to be used. Written directions should also be 
given, or a small chart placed in a corner of the drawing, indicating the con- 
ventions used in designating the various materials. 



TRACING, LETTERING AND MOUNTING 



25 



Following is a list of representative colors used in many offices: 

Cast iron Payne's gray. 

Wrought iron Prussian blue. 

Steel Crimson lake and small quantity of blue. 

Brass Yellow. 

Copper Crimson lake and yellow. 

Brick Crimson lake. 

Wood Burnt sienna. 

Earth .Daubs of ink, Payne's gray, etc. 

In the absence of Payne's gray, a pale wash of India ink in which 
has been mixed a little Prussian blue may be substituted. Very neat 




Fig. 18. 



F.g.19 



Fig. 20. 



N 



Fig. 15 




6'-6 



Fiq:i7 



sectioning can be made with crayons, toning them down with a soft 
rubber. 

Dimensions and Center Lines 

Working tracings should have the dimension lines, center lines and 
all lines black ink, the idea being to make a neat, distinct tracing for 
use only, whereas a show or estimate tracing should be made with 
greater care. It is a well-known fact that many contracts have been 
awarded on the merits of a well-executed piece of work by the drafts- 
man. The time and expense spent upon making a neat show tracing 
is never lost. Make the center lines of red ink or color, a fine long 
dash and dot line; make dimension lines either one continuous line 
broken only where the figures come, or a dash and dot line, as in Fig. 17. 



26 



No. 2 DRAFTING-ROOM PRACTICE 



Border and Cutting--off Lines 

Simple as these may seem, yet many well-executed tracings have 
been spoiled by either neglecting a border line or making a very 
poor one. A one-line border is perhaps the best and its thickness 
should match the work in hand, together with the size of the sheet. 
There should be plenty of margin between the border line and the 
work. A fancy border line, of which a few samples are given in Fig. 
18, may be put around estimate or show tracings. The cutting-off 
line should not be too near the border line, say, from % inch to 1 
inch. Nothing looks worse than to see a good tracing spoiled by cut- 




Fig. 21. 



L 

rig. 22 



L 



Fig.23. 




Fig.24 




Fig. 25 

Figs. 21 to 25 

ting off within a quarter of an inch of the border line (compare Figs. 
19 and 20). The initials of the draftsman and date tracing was made 
should not be omitted. 

Miscellaneous Directions 

Attention to details is perhaps the true secret of making a neat 
tracing. No matter how trifling a detail may seem, it should be made 
as neatly as the rest of the work. Channels, angles, etc., in section, 
should be made accurately, as in Fig. 23. Do not make them, as is so 
-often done, like Fig. 22. 

When tracing a blueprint, the tracing should be tacked down with few 
tacks, as it will have to be lifted quite often to see the work distinctly; 
in fact, in^TQany cases it would pay to make a drawing from the blue- 
print and trace it. Drawings which are faint or unfinished should by 
all means be made clear before attempting to trace them, thereby sav- 



TRACING, LETTERING AND MOUNTING 27 

ing much patience, but in particular the eyesight. In tracing from 
another tracing, a clean sheet of white drawing paper underneath will 
make it stand out clearly. If the draftsman understands what he is 
tracing, the work will be much easier and he will not be likely to 
make so many mistakes as he would if tracing a number of meaning- 
less lines. 

The tracing should be wiped down occasionally with a clean, dry 
duster or cloth. Cotton sleeves are sometimes used to protect the 
coat. A sponge-rubber or piece of bread may be used to clean a trac- 
ing, but if proper care has been taken, a tracing can be taken up as 
clean and neat as when tacked down. A greased, soiled tracing shows 

POSITION or CYLINDERS. 

STARBOARD ENGINES. 




THE GLOBE IRON WORKS CO. Y - 

CLEVELAND. OHIO. 

SCALE 5-I-O" JUNE6 TH I89O. 

Fig. 26. Example of Lettering a Drawing Title 

a had workman. In some offices it is the practice to sponge the trac- 
ings down with benzine. Waterproof ink must be used by all means 
if this plan is adopted. When the tracing is complete, the draftsman 
should look over it carefully, trying to detect any errors, as all such 
count against him. The shop hands, as a rule, are only too pleased to 
point out any trifling mistake coming from the drawing office. Accu- 
racy, as well as neatness and quickness, is desirable. 

Lettering 

No matter how neatly or carefully the working lines of a tracing 
are made, if the lettering and figures are not satisfactory the trac- 
ing will look poor in every sense of the word. The young draftsman 
should, therefore, take especial care to get into a neat way of letter- 
ing, and should devote a little of his spare time each day to this end 
if he wishes to excel as a neat draftsman. Neat letterers are in 
demand and are always sure of a position. Many cases are known, for 
instance, where a good letterer has been employed in his spare time 
to put on the figures and letters of other men's work, and although a 
poor tracing can be improved by neat lettering, to excel in both should 
be everyone's desire. 

A good instruction book on this subject is difficult to find. Most 
alphabet books are ridiculous in the extreme; it would take longer to 
make the letters they describe than the whole tracing. The tracings 
would look insignificant in comparison with the wonderful lettering. 
The letters and figures must conform to the other work neither 
should be more conspicuous than the other. For this reason it is 



28 No. 2 DRAFTING-ROOM PRACTICE 

preferable for each man to complete his own tracing. It is an easy 
matter to tell who made the various tracings in most drawing offices 
by the peculiar characteristics of each draftsman this one by its 
poor lettering or that by a beautiful harmony of lines, letters and 
figures, the whole standing out in correct proportion, fine lines having 
small neat figuring, lettering, and narrow, points to match, or heavy 
lines vice versa. Nothing looks more uniform, neater, or is quicker 
done than good, plain, one-line lettering, even for the titles, though 
perhaps a little display may be given to them. 

A few samples are here given. The small letters are for the general 
working parts of the tracings, notes, etc. Headings should be a little 

The fol/ow/rw a/phafafe are 'usea 'in 'maffoff/ces ' e/r?p/0y/f70 /nec/Mway/ 
orsfrvcfora/ dm ugh fewer?. T/?e sfodenf jfov/d pr#tf/e ffr&e vrif//' 
he gets /nfo a free greasy way 0f /effer//?(7 Me ^hov/d partf/ce /fftf/r/w 



GENERAL PLS7NS 



& ROLLING MILLS. 
COLUMB/S7 //?ON 



Fig. 27. Examples of Lettering 

larger, and the title, which will be referred to later, should be distin- 
guished from . the rest of the work by using large letters, either 
blocked out, or capital letters made with a heavier pen. Figures should 
be made plain and simple, without the use of flourish or tail-piece. 
Fractions should be made with one figure immediately over the other, 
instead of to. one side. The vertical system of figuring is preferable 
to the slanting, especially with shop tracings. 

For lettering, have plenty of black ink, but not too thick. The best 
kind of pen points are Esterbrook's No. 333, or Gillot's 303 for fine 
work. A heavier pen must be used for titles. Make the letters and 
figures with one stroke of the pen; do not go .over them again, but 
get the required thickness, even with titles, by bearing on the pen 



TRACING, LETTERING AND MOUNTING 29 

more. A pen can be tempered, when new, by holding it in the flame of. 
a match, though pressing it on the thumbnail is generally sufficient. 

Heading-s or Titles 

The heading or title should be in a conspicuous place, and as far 
from anything which may tend to crowd it as possible. The bottom 
right-hand corner of the sheet is a good place. A heading sometimes 
looks better without lines drawn underneath, as shown in Fig. 26. 

abedefqhijklmnopqrstuvwxyT, 

ABCDEFGHUKLMNOPORSTUI/WXYZ. 



ABCDEFGHIJKLMMN 
AIOPQRSTUVWXYZ 

ABCDEFGH JKLMMN 
AIOPQRSTUVWXYZ 

abcdefghijklmnopqrstuvwxyz. i 345^76 QO. 

Pig. 28. Alphabets for Lettering on Drawings 

This is entirely optional, however; if lines are put under they should 
not be too close to the letters. Black letters are sometimes used, 
which can be made by drawing six pencil lines equally spaced, as 
shown in Fig. 24. The T-square and triangle are used, and the letters 
can be made quite rapidly. They should afterwards be filled in, or 
one edge of the letters made heavier, acccording to the nature of the 
work in hand. Sloping letters can be made in the same way by using 
an adjustable-headed T-square or a special triangle made for that 
purpose. 

Stenciling- 

Sometimes headings, letters, figures and corner pieces are put on 
by means of stencil plates cut out of tin or copper sheets. A stiff, 
short stencil brush is used. The brush is moistened with water, not 
using too much, and is then rubbed along the stick of ink until it 
cannot absorb any more. Particular attention is called to this, as 
here is where so many fail in making clean and clear stencil work; 
the brush should never be dipped into a saucer of ink, or the ink 
applied with a pen. 



30 No. 2 DRAFTING-ROOM PRACTICE 

The position for the title having been settled, pencil lines should 
be drawn on the cloth as a guide for the stenciling. Sometimes the 
title or heading is stenciled upon a spare piece of cloth or paper 
first, then slipped into place under the tracing and the stencil work 
done over it. This is a good plan, as the correct position may thus be 
obtained. If this is not done, the only way is to make a pencil tick 
mark after each letter to indicate the position of the next, as, of 
course, the stencil plate will hide all beneath it except the letter being 
stenciled. Then the letters must each be filled in, as shown in the 
first two letters of Fig. 25. 

Even when the stencil guide referred to is made and slipped into 
place under the tracing cloth, a pencil guide line should be drawn and 
all letters stenciled exactly to it. The pencil lines and ticks are then 
erased. If the brush becomes dry, it may be moistened on the tongue 
without again rubbing it on the ink stick. Draftsmen sometimes cut 
their own stencil plates out of stiff drawing paper, applying a coat of 
varnish on the upper surface. 

Round Writing- 

When referring to alphabet books, the writer should have made one 
exception at least, and that is the round writing system. It is easily 
learned and not soon forgotten. Letters and figures of all sizes and 
shapes can be made by using different graded pens. Books of instruc- 
tion and an assorted box of pens may be had from any stationery store 
of importance. 

Mounting 1 Tracing- Paper 

Tracings likely to be in hand a long time should be mounted to the 
drawing board, for several reasons. They will be protected from get- 
ting torn and will not shift on account of the sudden change of tem- 
perature of the room which may take place; they can also be cleaned 
more safely than if held by a few tacks. The paper should be cut large 
enough to allow for sticking the edges to the board, and should it be 
intended to color the tracing with liquid colors, twice the allowance 
should be made, as the paper will be cut after the tracing is made, 
and mounted the second time. The drawing to be traced should be 
laid down square with the board perfectly flat and level, then thor- 
oughly dusted down to remove all obstructions, as these cannot be 
removed after the tracing paper is mounted. 

A long, flat straight-edge with a couple of weights for each end is 
needed. Having cut the paper, dampen it slightly with a wet sponge, 
going over it very evenly and working quickly, so that it may be 
attached to the board before quite dry. The damp side must be up. 
The straight-edge is placed an inch outside of the cutting-off line and 
the weights put on, one at each end. Turn up the edge of the tracing 
paper, as shown in Fig. 29, and apply the mucilage or paste brush, 
pressing the edge down firmly with a straight-edged ruler or paper 
knife. The opposite side of the tracing paper is treated in the same 
way, and then the two remaining sides, care being taken to stretch 



TRACING, LETTERING AND MOUNTING 31 

the paper carefully by pulling the edge of the paper gently with the 
tips of the fingers, before the weights are put on the straight-edge. 
Any superfluous water may be removed with a blotter. The whole 
operation, as before stated, should be done very quickly, as in a warm 
room the paper soon dries. 

Mounting- Paper for Coloring- 
Should there be any wash coloring to be done after the tracing is 
made, it is usually done on the back. The tracing is therefore taken 
up, cutting close to the pasted edge, so as to leave as much margin as 
possible for the second mounting. TTie drawing paper is also taken 
off the board and a clean white sheet, not so large, put in place of it. 
The tracing paper, being turned over, is again mounted to the board 
as previously described, care being taken to get no paste inside the 
cutting-off line, which should have been distinctly marked. While the 




Fig. 29. Mounting Tracing Paper 

paper is drying the colors can be mixed. Allow the coloring to thor- 
oughly dry before cutting off the tracing, which should be done with 
a sharp knife, following the cutting-off line very carefully. 

Mounting- Cloth for Tracing or Coloring- 

The process described above is for paper tracings only. Cloth can 
be mounted in the same way, except that on no account should a damp 
sponge touch it, but it may be stretched without damping it at all, 
though not so satisfactorily. If the tracing cloth is put in a cold 
or slightly damp place over night it can be stretched very nicely, 
using a thin glue instead of paste. When one edge is firmly fixed, the 
other should be pulled very tight and extra weights put on the straight- 
edge to hold it in place while applying the glue brush. Mounting for 
coloring is done the same way, it being, of course, understood that 
the coloring is done only on the dull side of the cloth. Very satisfac- 
tory results can be obtained by not mounting tracing cloth at all, but 
simply using a number of iron tacks driven with a magnetized ham- 
mer, as elsewhere described. 

Mounting- Blueprints, Maps, Etc. 

Blueprints, maps, drawings, old tracings, etc., are often mounted on 
linen or cotton to preserve them. The linen or cotton should be cut 
larger by several inches than the blueprint, and a drawing board about 
the same size used. Soak the linen well in water, wringing it out 
between the hands until all the superfluous water is squeezed out, 



32 No. 2 DRAFTING-ROOM PRACTICE 

when it should be unfolded and shaken out. Lay it across the board 
and commence tacking one edge, beginning at the center and pulling 
gently; place a tack about every two inches along the edge of the 
board, as shown in Fig. 30. The other half of the same edge must 
be done in the same manner. The opposite edge is done next, stretch- 
ing the linen well each time before a tack is driven; commence at the 
middle as before and work toward each end. The two remaining 
edges are done in exactly the same manner, and all is now ready for 
the paste, which should be prepared for use before the linen is 
stretched. The paste can be made either of starch or flour. A suf- 
ficient quantity is mixed in cold water to about the thickness of cream. 
Hot water is then poured over it, gently stirring it meanwhile; the 
whole is then put in a saucepan on the fire and stirred until it begins 
to boil over, when it is lifted from the fire, poured back again into 
the basin, and is ready fffr use. An apron of some kind is fastened 
around the neck, reaching to the knees, to protect the clothes from 





Fig. 3O. Mounting Blue-prints and Maps on Linen 

getting soiled. Taking some of the paste in the hand, slap it over the 
board, rubbing it well into the linen with both hands, using more paste 
if required, until the whole surface is covered. Now, commencing at 
the lower edge and at the left-hand end, holding the tips of the fingers 
close together push the superfluous paste along to the center of the 
board as you travel along from left to right. Go to the opposite side 
of the board and do the same thing, forming a ridge of paste along 
the middle of the board, which is scraped off with the hand into the 
basin. With both hands go all over the board again until the paste 
is nicely and evenly spread all over the linen. 

An assistant is now required. The blueprint is dampened on the 
.back with a sponge and placed gently in correct position on the linen. 
One-half is to be pasted at a time. The assistant holds it up by the 
two corners at an angle of about 30 degrees, while with a large blotter 
in one hand held to the print you rub gently but firmly over it, the 
assistant letting the print gently yield to the pressure you bring to 
bear upon it. Passing over to the other half, it is lifted from the 
board and then treated in the same way. Wherever an air bubble 
appears it can be pricked with a needle, and the blotting pad placed 
over it, while with a circular sweep of the other hand you press it 
firmly to the board. Should any obstruction unfortunately have been 
left between the print and the linen a slit can be made in the former 
and the obstruction removed when it is again pressed to the board. 



TRACING, LETTERING AND MOUNTING 33 

The whole should thoroughly dry before any attempt is made to 
tear it from the board. Often this is not done till the following day. 
Cut through the print and linen with a sharp knife along the cutting-off 
line all around the board. Then, lifting the corner, pull gently but 
firmly in a slanting direction. The tacks and trimmings are then 
removed and the board cleared away. The case of a blueprint has 
been taken. Maps, drawings, etc., are done in precisely the same 
manner. Before the print is taken up, a coat or two of clear copal 
varnish is sometimes applied to preserve it still more. 

Mounting- Paper on Drawing- Board 

A quick and very satisfactory way of mounting drawing paper to 
the board, instead of using tacks, is resorted to by many draftsmen 
in the following manner: The paper is laid flat on the board, right 
side up. A moderate sized sponge filled with water is wiped all over 
the surface of the paper within an inch or so of the edge all around. 
The superfluous moisture is mopped up with the sponge, and the edges 
then dampened. One half of the sheet is turned precisely over the 
other half, edge for edge. With a well-filled mucilage brush go quickly 
around the three edges of the upturned half of sheet, and turning it 
over again, press the edges firmly to the board with the thumb or a flat, 
thin stick. Turn the other half of the sheet over the first and proceed 
in the same way. When thoroughly dry, the paper will stretch very 
satisfactorily. 

Still another way of mounting paper is to lay the sheet down wrong 
side' up and with a small glue brush dipped in liquid glue go all 
around the edge of the paper at once. Quickly sponge all over the 
surface with plenty of water, keeping clear of the glued edge. Having 
mopped up the superfluous moisture with a dry sponge, turn the paper 
completely over and stretch it to the board by going over the surface 
with the flat of the hand or a clean, dry duster, working from the 
center to the edges, pressing the latter all around firmly to the board 
with the flat of the thumb or a thin, flat stick or ruler. Either of 
these methods has been successfully used in many offices, especially 
architects', but for important work the method described under the 
head of "Mounting Tracing Paper," and illustrated in Fig. 29, should 
be resorted to. 



CHAPTER III 



CARD INDEX SYSTEMS 

It is evident that the index system suitable for one drawing-room 
may not be exactly what is wanted in another, where a different prod- 
uct of manufacture, and different conditions in general, call for some 
individual modifications. It is therefore necessary to assume, perhaps, 
that the index systems outlined in the following may not be directly 
applicable to a majority pf drafting-rooms, but the general principles 
involved will be, and ought to be, used as guides in devising any 
drawing-room card index system. 

Index System for Drafting-room with a Great Variety of Work * 
The greatest difficulty in devising a satisfactory index system is 
met with in shops having to deal with a great variety of work. For 
drafting-rooms in shops where the product is limited to only a few 



Drawing No. A-612 Date March 6 1905 

Drawn by M. -r Checked by Potter 

Casting Detail : 

Special head for #2 

Brown & Sharpe Milling Machine. 
Piece No. 656 

Remarks: For construction see A-109. 
For milling hexagon nuts. 



Fig. 31. Index Card for Shop Drawing 

standard machines, or articles, which are turned out in great quanti- 
ties, the problem is a comparatively easy one. But in the case where, 
even if the shop be comparatively small, the accumulation of drawings, 
sketches, patterns, and such tools as the drafting-room is often ex- 
pected to take care of, becomes of a vast scope even in a few years, 
on account of the variety of work, a more detailed system becomes 
necessary. 

The system indicated in the following may, at first glance, seem 
somewhat elaborate, but a little extra expense added in the beginning 
will more than repay itself in the long run. The main factor to be 
taken in consideration when planning a system is, of course, the 
rapfdity with which a thing looked for can be found. The somewhat 



* MACHINERY, September, 1905. 



CARD INDEX SYSTEMS 35 

greater care needed to keep up a complete system will hardly amount 
to anything compared with the time wasted in trying to locate things 
looked for in an incomplete and patched up card index system. 

The words, "drawing," "shop sketch" and "customer's sketch" re- 
ferred to below are defined in this system thus: 

Drawing. Any tracing or drawing for machines, tools and devices 
manufactured by the firm as a standard article or used in the shop. 

Shop sketch. Any drawing, made in the drawing-room, of special 
tools that are ordered in small quantities by customers. 

Customer's sketch. Any drawing, tracing, sketch or blueprint that 
has been sent to the firm by outside parties or customers. 

The drawings are indexed on cards (see Fig. 31) on which is stated: 

1. Number and letter of drawing (the letter indicating the size of 
the drawing). 

2. When made. 

3. By whom made. 

4. By whom checked. 

5. Complete title of the drawing. 

6. Piece number (if a casting, this is also the pattern number). 

7. Remarks. 

These cards are numbered, when they are blank, with the drawing 
numbers in rotation, and are kept in numerical order. As soon as a 
drawing is made, the first blank card is filled out and its number 
stamped on the drawing. The card is then placed in the index, accord- 
ing to the- following rules: In the first place, tools and machines 
should be indexed in general classes, and all general attachments for 
the machines should be indexed under the heading of the machine 
with which they are used. For example, cutters of every description 
should be indexed under the word "Cutter," and sub-headings should 
be provided in the index if the number of cutters of different descrip- 
tions make a sub-division necessary. Again, for example, "Dividing 
head for milling machine" should be indexed under "Milling Machine" 
and sub-divisioned under "Head." Fig. 32 of an index arranged in 
this manner will make further explanations unnecessary. 

Jigs and fixtures that are to be used for certain operations in 
manufacturing parts of standard machines and tools are indexed in 
the same divisions as the parts on which the operation is to be per- 
formed are indexed under; for example, a fixture for boring head for 
milling machine is indexed under "Head" for "Milling Machine." In 
cases where it is found difficult to decide under which heading to 
place a certain tool or fixture, it is advisable to make out two % or 
even more cards under such headings where they are most likely to 
be looked for. The files for the cards should be kept in the most 
accessible place in the drafting-room, where everybody having to use 
them can do so with convenience. 

The drawings are filed in drawers in the drawing-room, out a "record 
blueprint" of each ought to be kept in a fireproof safe or vault; of 
course one must be very particular about replacing these "record blue- 
prints" every time a change is made on the original tracing or drawing. 



36 



No. 2 DRAFTING-ROOM PRACTICE 



Sketches, as a rule, being used only a very limited number of times, 
ought not to be traced, but drawn either in copying ink or copying 
pencil, and copied in a special copybook used for the purpose. The 
sketch is marked with the page number of the copybook where it is 
copied. These sketches could, of course, be indexed on the index pages 
of the copybook, but when one copybook after another is filled out it 
would be a waste of time to have to go through the index of each 




Machinery, ff.T. 
Fig. 32. Arrangement of Index Cards in File 

one in order to find what is wanted ; therefore a card index is provided 
for these sketches also, where the cards are put in order according 
to the names of the customer. 

There is also an additional card index for these sketches where 
the cards are put in order, not with reference to name of customer, 
but according to name and kind of tool drawn on sketch. Customer's 
sketches are not listed in any card index, but are kept in proper order 
in a common letter-file. 

There is no need of providing for a card index for the patterns, as 



CARD INDEX SYSTEMS 37 

the pattern numbers are always marked, not only on the drawing itself, 
but also on the index card for the drawing in question. However, it 
is both convenient and necessary in many cases to be able to tell from 
the number of the pattern what machine or tool this pattern applied 
to; therefore a book is provided with pattern numbers in rotation, 
where the patterns are entered as soon as a drawing is made. 

It is not only necessary to keep a good record of drawings or pat- 



No, of copybook 6 Page 314 Date March 12 1905 
Drawn by G. R> Checked by Potter 

Customer's name : American Tool Works Co. , 

Cincinnati, Ohio. 
Tool: Taper Reamer- 
Remarks: For Brass made to their sketch. 



Fig. 33. Card in Index Arranged According to Name of Customer 

terns that have been made, but equally as important to have a com- 
plete record of blueprints, sketches, patterns, etc., when in use. All 
blueprints given out from the drawing-room must be charged to the 
person for whose use it is furnished, whether he be some one in 
the shop or an outside party. For this purpose there is a special set 
of cards, one card for each drawing, this card being provided with the 
drawing number; these cards are kept in numerical order. When a 



No of Copybook 6 Page 314 Date March 12 1905 
Drawn by G. R. Checked by Potter 

Tool: Taper Reamer. 

Customer's name : American Tool Works'Co. , 

Cincinnati, Ohio. 
Remarks: For brass made to their sketch. 



Fig. 34. Card in Index Arranged According to Class of Tool 

blue-print is given out by the drafting-room, the name of the person 
for whose use the blue-print was given out, is recorded v on the card 
with the same number as the drawing. This enables anyone to find at 
a glance where every blueprint of a certain drawing can be found. 

When sketches are sent out in the shop, it is noted in the copybook 
itself on corresponding page, to whom and on what date, sketch was 
given out. As these sketches have to go from one department to 
another, each department foreman is expected to -keep a record of 



38 No. 2 DRAFTING-ROOM PRACTICE 

when and to whom he sent the sketch, when he was through with it. 
When the work is finished, the sketch is returned to the drafting-room 
and the date when it was returned is noted down in the copybook on 
page number corresponding with sketch. Customer's sketches are 
never sent out in the shop, but are kept as records and for reference 
in the letter-file mentioned above. 

A system laid out and made up in accordance with the principles 
above will prove itself very satisfactory, not to say necessary, for the 
drafting-room in a shop having a great variety of work to do. 

Card Index in the Jobbing- Shop * 

The index system of the drafting-room in a general jobbing and 
repair shop also offers difficulties. The system for such a drafting- 




Fig. 35 

room, as outlined below, has been devised by a man in charge of a 
shop doing a general line of repair work and some building of new 
machinery, in a place where there is little scope to take up any 
standard line of work or even to make the same machine twice with- 
out alteration. To avoid endless confusion, he has found it necessary 
to evolve some system of keeping records of the machines and parts 
of machines sent out, as well as of the drawings, and his experience 
undoubtedly will prove useful to others having to work under similar 
conditions. 

In most shops of this kind a part of the work is done to blueprints 
or sketches supplied by the customer, and part to drawings made by 
the firm's own staff; and the patterns are sometimes the customer's 
property and sometimes the firm's. The remainder of the work is 
repairs, overhauling, refitting, etc., of which no record need be kept. 
The problem resolves itself into these requirements: First, to be able 
to find at any time the drawing to which any part of any machine 
w r as made, given the customer's name. Second, to have a complete 

* MACHINERY, June, 107. 



CARD INDEX SYSTEMS 39 

index to all patterns, drawings, foreign blueprints, etc., to save duplica- 
tion of any of these where they can be worked in on another order. 

On receipt of an order from a customer it is written out on a 
form, a copy of which goes to the drawing office, pattern shop, boiler 
shop and machine shop, or such of these departments as have work to 
do on that order. 

We will suppose that this order is for a machine to be made to the 
firm's own drawings. The drawing office then, on receipt of this order, 
makes out a production sheet on bond paper forms, giving name and 
number required of each part, drawing number, pattern number if a 
casting, and material of which it is made. This production sheet 
should include everything required, bolts, nuts, oil-cups, gaskets, split 
pins, name-plate and every detail, no matter how small. In the case 



2 I . - - ^Z. H T'-O" .- eo '> F\. 

5. - -- *<e>-r"- fES> '. \S> V\ 

IT. " - ^ST x T.'-O' - \ <O 10 f 



Fig. 36 

of forgings, it should give, in addition to drawing number, the length 
and size of bar required to make it. The required number of prints 
should then be made from the production sheet, and the order number, 
name of customer, date issued and number of machines required (the 
production sheet should always be made out for one machine only) 
put on the prints, and not on the original, as this may be used again 
later, on other orders. One print should then be sent to the stores 
department, to order the material from, and one to each of the different 
departments having work to do on that order, the pattern shop having 
to issue the patterns and orders to the foundry department. Also one 
print should be filed away as a record under the order number, prefer- 
ably in an envelope, together with any special specification or other 
matter referring to that order only; these will be kept in numerical 
order and should be stored in a fireproof vault, but in a convenient 
place for reference. The original can now be altered to suit any 
future orders or improvements in design without affecting our record 
of that order. Any alterations to the drawings for subsequent orders 



40 No. 2 DRAFTING-ROOM PRACTICE 

are also made in such a way that there is a record of the original di- 
mensions. 

Now, to duplicate any part of an old order, we have a card index 
of the production sheet prints that are filed under their order num- 
bers. These cards are indexed alphabetically under the customer's 
name; a copy of the card is shown in Fig. 35. This card is filled out 
for each order for that firm and filed away in the index cabinet. 
Therefore, given the customer's name, we can, by consulting this index, 
find the order number under which his machine was built, and by get- 
ting out the production sheet print for that order number we get the 
drawing numbers we require. 

The columns for size and hand save us the necessity of looking up 
two or three production sheet prints, as, for instance, if we get an 
order for a set of grate bars, same as supplied by us with a 48-inch 



\-0 
\\\-B 



Fig. 37 

boiler for Brown & Co., we look under Brown for Brown & Co.'s card, 
and then down that card till we come to a 48-inch boiler, which will 
give us the order number, and from the production sheet print for 
that order number we can get the pattern number and number re- 
quired. If we had not the size on the card we might have any num- 
ber of boilers built by us for that firm to look up in the production 
sheet prints before we found the 48-inch size. 

The Machine No. column is used in case a customer sells his ma- 
chine to some one else, the number being stamped on the name-plate 
of the machine. 

The Drawing No. column gives the assembly drawing number, and 
may save time if one wanted only an assembly drawing, but it is 
primarily intended for orders such as stacks, smoke connections, etc., 
which require only one drawing. No production sheet is made for 
such orders, a bill of material on the drawing giving all information 
required. 



CARD INDEX SYSTEMS 41 

The original production sheets have a card index with alphabetical 
guide cards, and are indexed under the name of the machine, as boiler 
under B. A copy of these cards is shown in Fig. 36. The production 
sheets are numbered in order, as made. The shop drawings are in- 
dexed alphabetically under the name of the part. These drawings are 
numbered and filed consecutively as made, and are given the suffix A or 
B. A is the large size (18 x 24-inch) and B the small size (9 x 12-inch). 
The A and B drs.wings are numbered and filed independently of each 
other. The cards for indexing these drawings are shown in Fig. 37. 
Each part of a machine is on a separate card, and the cards are re- 
written from time to time to keep the parts on the card in order of 
size, smallest size at top^ as other similar parts of different sizes are 
made and interpolated. 

If the order should be to make a machine to the customer's blue- 



t- > C >' 



- \-\o <*& . 

P CO=N\_ to ' ~"b'- o" So 

Co < - 3' -<+-"* &o'- o" re.. 

-> ' - - *<2o'-o" Tt . 

Co , - - "$-<&' x,&>^'-d' &4- 

$> c.o. 

co 



Pig. 38 

prints, we number these prints consecutively, starting with the num- 
ber after that given to the last blueprint on the previous order, and 
giving it the suffix C or D, as 125-C. The suffix C indicates that the 
patterns shown on that print are our property, and the suffix D indi- 
cates the reverse. These prints are folded and put in envelopes bear- 
ing the same number, and are filed away in consecutive order, the C 
and D prints being in separate drawers. The C prints are indexed 
with our own A and B drawings, so that we have on the cards a com- 
plete list of all sizes of patterns or designs we have of that particular 
part. The D prints are indexed under the name of the part, the card 
being shown in Fig. 38. The column for print number is for the num- 
ber given the print by the customer, and Name of Firm is the name of 
the customer or owner of the print; these two columns are for pur- 
poses of ready identification. 

The foregoing is only a bare outline of the system, but it will be 
sufficient to show its cheapness and adaptability to the work required 
of it. 



42 No. 2 DRAFTING-ROOM PRACTICE 

Limiting the Volume of the Card Index * 

While the card index has proven a valuable aid in facilitating the 
drawing-room work, it is, however, apt to become rather voluminous 
if the business is a growing one, and even though one may add all 
the card index guides possible, dividing the index into classes and sub- 
divisions, there will invariably be some sub-divisions that will contain 
more cards than are convenient to look through every time a drawing 
is to be found. 

For this reason a, system based upon a principle of classification, as 
described below, will make the index less voluminous, and at the same 
time permit a saving of time when looking up a drawing. It is the 
usual practice to make one card for each drawing indexed. This is, 
however, not necessary as long as there will always be a certain num- 
ber of drawings of the same kind of tools or articles that can conven- 
iently be listed on the same card. The card depicted in Fig. 39 shows 



CLAS 
SUBI 


>s IV 


tilling Machine Fixtures, 
ixtures for parts of Multi-spindle Drills. 

FIXTURES FOR FEED RACKS. 


)IVISION . . F 
] 


No. of 
Draw- 
ing. 


Date 
Issued. 


Drafts- 
man.. 


Description. 


Date 

Superseded 


2716 
3563 
4716 
4719 


,6 13-1904 
9-27-1905 
12-30-1905 
12 31-1905 


Smith 
Leland 
Leland 
Leland 


For 4-spindle drill, If 
center distance. 
For 3-spindle drill, If 
center-distance. 
For 4 spindle drill, 2$ 
center-distance. 
For 4-spindle drill, If 
cen ter-distance. 


12-31-1905 








Fig. 39. Index Card Adopted to Save Space 

plainly the principle employed in regard to using the index guides, 
having first guides for general classes, and then for sub-divisions. On 
the third line of the card is given the general name of the class of 
articles for which the drawings on this card are made. The remain- 
der of the card can be used for filling out from time to time addi- 
tional drawings belonging to this same general description. It will 
be seen that by means of this system the card index can be easily 
reduced to a fraction of its original volume. As the draftsman is well 
aware, the average life of a drawing is rather short, and still, as super- 
seded drawings have often to be referred to, it is well to systematize 
the drawing-room so that the superseded drawings are kept on file 
right with the regular ones, but marked "superseded," and with the 
date the reissue took place. In order to save unnecessary delay in 
looking up a drawing, the date when the drawing was superseded 
should also be marked on the card in the index. With the exception 
of these remarks, the picture of the card will explain its purpose, and 
* MACHINERY, September, 1000. 



CARD INDEX SYSTEMS 43 

its general usefulness. Systems of this character have proved a time- 
saving suggestion to many drawing-rooms that used to work under 
difficulties with rapidly expanding card-index systems. 

Blue-print Record Card * 

A firm whose line of work is such that improvements and changes 
of designs and details are constantly being made, must by necessity 
devise some system of properly keeping track of the blue-prints in the 
factory. In an establishment where there are several hundred prints 
in twenty to twenty-five different departments, it is very necessary that 
there be some good system of keeping in touch with every blue-print, 
in order that the proper ones may be corrected when a change is 
made. 

The card shown in Fig. 40 is one used to great advantage by The 
Garford Co., to keep track of all blue-prints issued from the drafting- 



' 

37 

DELIVERED DEPT CONDITION CHANGED CHANGED CHANGED ' CHANCED RETUHKEO REMARKS 

UNMOUNTED " x # 

or/fi&,nrrtst,rir/7yL S^ses,7-, 

BSSfffi^^fS 3 } 1 ^^ *#^Z*!!L 




J11Q l ' 

PWffi ^ s? ~ 

07. <?. MACHINE fatty 



Fig. 4O. Blue-print Record Card 

room. Each detail is drawn on a separate standard sheet, and mounted 
on pressboard for the shop. Each department has a complete book 
of blue-prints for each type of machine. When a change is made on 
a drawing, a new blue-print is made to supersede each blue-print in 
the factory. On issuing a blue-print from the drafting-room, a card 
like that in Fig. 40 is filled out. The name of the piece is entered 
in the place marked "Name." Blue-print number, and drawer number 
(which is the drawer wh'ere the tracing is filed) are placed on with a 
stamp in their proper places. In the column marked "Delivered" the 
date is entered, and the department number placed in the column 
marked "Dep't." Under the heading "Condition," the mounting and 
kind of the blue-print is noted, either mounted or unmounted, machine, 
drop-forge or pattern drawing. For this, a rubber stamp is used. 
When a change is made in the tracing, by looking on the proper card. 

* MACHINERY, August, 11)07. 



44 No. 2-DRAPTING-ROOM PRACTICE 

it is readily seen where the blue-prints are, and which ones are to be 
changed. In the column "Changed," the date when the new blue- 
print is delivered and the old one is returned, is noted. If for any 
reason it is not necessary to change the blue-print in some depart- 
ments, a check or some other mark is placed in the space instead of 
the date, and a similar check or mark placed on the back, and the 
reason noted. If, for instance, the piece is a casting and some drilled 
hole were changed from one-quarter inch to three-eighths inch, it 
would not be necessary to change the blue-print in the pattern shop. 
Each department has its own blue-prints, and they are never delivered 
from one department to another without first going through the draw- 
ing-room. When a department is through with the blue-print, it is 
returned to the drawing-room, and the date entered in the column 
marked "Returned." 

Card Index for the Draftsman's Individual Records * 

While in the up-to-date drafting-room the card index found early 
acceptance, and has become a necessary adjunct for the keeping of 




Fig. 41. Card Index for the Draftsman's Individual Records 

records of various kinds, there is, however, a place in the drafting 
room for the card index where it has yet to be more generally adopted, 
and that is as an individual adjunct to each draftsman's outfit. Years 
ago Nystrom said: "Every engineer should make his own pocketbook, 
as he proceeds in study and practice, to suit his particular business," 
and there is no better way of compiling a pocketbook than by the use 
of the card index. Outfits for the purpose may be purchased in all 
styles and prices, from the trial outfit of 3 x 5 cards, in & pasteboard 
case and costing about 75 cents, up to the most elaborate cases and 
trays for the 5x8 cards. 



* MACHINERY, November, 1903. 



CARD INDEX SYSTEMS 



45 



Fig. 41 is a sketch of a very cheap and serviceable index box that 
can be readily put together in the pattern shop, and is in some ways 
better suited to this particular purpose than those purchased of the 
regular dealers in such goods. Being made of %-inch pine, planed 
down to about % inch, it is very light and much more easily handled 
than the regular cases, which are usually made of oak. Another point 
in its favor is that it can be made much shorter than any, of the regu- 
lar trays which come in lengths of from 12 to 14 inches, and are, there- 
fore, of a size that would prove unhandy upon a draftsman's board. A 
package containing 100 index cards of medium weight measures a 
little less than an inch in thickness, so that a box 4 or 5 inches deep 
will hold a sufficient number of cards to cover a long period of the 
average draftsman's experience. The object should be to compress 



PROPORTIONS OP GEARS. (By c. F. Blake.) 




p = circular pitch. 
R = pitch radios of gear in inches. 
n = number of arms. 
N = number of teeth. 

W = load at the pitch line = p f y ( from above 
table). 

WR spfyR 
Bending moment in each arm M = - = - 



For Elliptical Sections. 



h = 



bm.tp 

Taper of h = 7-16 inch per foot. 
Taper of Z> = 5-16 inch per foot. 

t = 0.47p 

t = OMp 



T = 



Fig. 42. The Card Index used for Clippings 

the entire outfit into size and weight which shall not greatly exceed 
that of an ordinary reference book. 

Cards for these outfits are provided mainly in 3x5-, 4 x 6-, and 5x8- 
inch sizes, but if the index is to be put to all of the uses which are 
mentioned later, the cards should not be less than the 4 x 6-inch size. 
Either of the two larger sizes, if used in a short, light tray, will be 
found fully as convenient to handle as the ordinary tray for the 
smaller cards when it is of the usual length and constructed of oak. 
The cards chosen should be of sufficient size to allow of fairly lengthy 
computations, and for mounting complete tables and similar data 
clipped from periodicals. If home-made cards are to be used they can 
be easily cut from manila or stiff white drawing paper, and will answer 
the purpose very satisfactorily. Guide cards are cut from the same 
material and labeled to suit the matter to be indexed. In the case 
illustrated no provision whatever is made for locking the cards in, as 
none is considered necessary. When it is desired to refer constantly 
to a certain card or cards they may be easily slipped out and placed 



46 



No. 2 DRAFTING-ROOM PRACTICE 



on the drawing board for the time being, and any device which makes 
it necessary to lock and unlock in order to do this, or to remove and 
add cards, will, after a short trial, be found to be more of an objection 
than an advantage. 

The uses to which the index can be put will suggest themselves to 
each draftsman as the requirements of his work present them. In the 
first place there are certain tables to which every draftsman must con- 
stantly refer, .and these should form a foundation of the index sys- 
tem. Such data as decimal equivalents, squares and cubes, trigo- 
nometrical functions, etc., furnish the most natural beginning. These 
are to be found in the handbooks in common use, such as Kent and 
Nystrom, but when only one table is needed for a particular use, the 
convenience of drawing out a single card over the necessity of hand- 
ling the whole book, will at once be apparent. Often several tables 




D - 



d/ff/nefer of w/'fr 



/27?/tf 2.'\ 
C0Mpress/0fl forecrc/r cw/ 



teqfrup's for/ni/Ja forcofnprettion 



s Substituting va/ues f/vm Tesf 



F* 



pe* 



{ For future ca/cv&t/ons use E' 



Fig. 43. The Card Index used for Record of Teats 

are used at the same time, and then the pages of the book must be 
turned back and forth, or, perhaps, two or more books must be referred 
to. With the index system any number of cards may be placed side 
by side where the draftsman may refer to them without trouble. 
Having started with the tables most commonly used the index will 
grow with considerable rapidity. If any unfamiliar table or data is to 
be consulted, much time may be lost in searching for it through the 
different handbooks, but if, when found, it is copied on to an index 
card, it is then ready for immediate use if again needed. Clippings 
from periodicals have before been referred to, and the value of a year's 
subscription to any good technical publication will be wonderfully in- 
creased if all of the data that is published pertaining to one's par- 
ticular line of work is placed upon the cards. Fig. 42 is an illustra- 
tion of a data card upon which is mounted one of the tables taken 
from a MACHINERY data sheet. 

Reviews of all technical books that the owner reads should find a 



CARD 'INDEX* 



47 



place upon these cards. To thoroughly digest any book there is no 
better plan than to make notes and extracts as the reader proceeds, 
and if these are afterward placed in his index, they will often prove 
of the greatest value. 

In many drawing-rooms the draftsman is provided with a note book 
in which to record all calculations, estimates, and other computations 
that may arise in connection with his work. After one of these books 
has been in use for several months, and a mass of calculations has 
accumulated therein, it is a most tedious job to search them over for 
the figures applying to the matter in hand. If, however, the calcula- 
tions are made upon index cards and filed under appropriate head- 
ings, they may be found at a minute's notice. 

A draftsman is often called upon to design certain pieces of mechan- 
ism in which the strength of the material must be taken from general 




/5/oec/cr/ Pcr/'fo 



Fig. 44. The Card Index used for Record of Special Machines 

data and may vary considerably from the strength of the material 
actually used. In such a case it may be practical to make subsequent 
tests and from these to obtain definite data. The card shown in Fig. 
43 is taken from an index compiled by a designer for the purpose of 
recording such data, and serves to illustrate the way in which the 
results of such tests can be kept for ready reference. The problem in 
this case was to design a spring that should stand a load of about 
25,000 pounds and to determine its deflection when loaded. The spring 
was designed and the compression figured by Begtrup's formulas, in 
which the modulus of elasticity is given as from 10,000,000 to 14,000,- 
000, and the exact modulus to be used is left to the judgment of the 
designer. After these springs were made they were tested, with the 
results shown on the card, and substituting the actual deflection for 
given loads we are able to determine a modulus of elasticity, in this 
case about 13,000,000, which can be regarded as comparatively exact 
data for use in designing springs that are to be made of the same 



*iv 

48 A-,. 2M:A?TJFG.-RQOM PRACTICE 

material and to perform similar duty. If similar comparisons be made 
of castings and forgings of various kinds, we soon accumulate a quan- 
tity of very reliable information that applies more closely to our par- 
ticular cases than any published data which must, at best, be only 
general in its nature. 

Photographs of machines built, and data connected with them, will 
prove valuable additions to the index. Fig. 44 shows a record of a 
special vertical milling machine, and explains just which parts were 
special and which regular, and provides a complete record of the draw- 
ings used and any information that would be of aid to the draftsman 
if called upon to design a similar machine at some future time. 



THIS BOOK IS DUE ON THE LAST DATE 
STAMPED BELOW 

AN INITIAL FINE OF 25 CENTS 

WILL BE ASSESSED FOR FAILURE TO RETURN 
THIS BOOK ON THE DATE DUE. THE PENALTY 
WILL INCREASE TO SO CENTS ON THE FOURTH 
DAY AND TO $1.OO ON THE SEVENTH DAY 
OVERDUE. 



REC'DlD NOV 3 P70 -10 AM 3 3 




YC 53944 



777 




UNIVERSITY OF CALIFORNIA LIBRARY 

**&&. . . 









I 



No. 4. Reamers, Sockets, Drills and 
Milling- Cutters. Hand ReqEmers; Shell 
Reamers and Arbors; Pipe R iper 

Pins and * Sharpe, 

Morse and Jar no T;iper Sockets and Ream- 
ers; Drills; \V : Milling- Cutters; 
Setting Angles for Milling Teeth in End 
Mills and Angular CuU< 

No. 5. Spur Gearing. Diametral and 
Circular Pitch; Dii., I' Spur Gears; 

Tables of Pitch D Odontograpli 

Tables; Rolliru ; Strength of 

Spur Gears; Horsepower Transmitted by 
Cast-iron and Rawhide Pinions; Design of 
Spur Gears: Wight of Cast-iron Gears; 
Epicyclic Gearing. 

No. 6. Bevel, Spiral and Worm Gear- 
ing. Rules and Formulas for Bevel 
Gears; Strength of Br\ : Design 

of Bevel Gears; Rules rind Formulas for 
Spiral Gearing; Tables Facilitating Calcu- 
lations; Diagram for Cutters for Spiral 
Gears; Rules and Formulas for Worm 
Gearing, etc. 

No. 7. Shafting, Keys and Xeyways. 
Horsepower of Shafting; Diagrams and 
Tables for the Strength of Shafting; 
Forcing. Driving-, Shrinking and Running 
Fits; Woodruff tilted Stat 

SuuuiMpbr Milling 1 

ways" JDui 

No. 8. Bearing's, Coupling's, Clutches, 
Crane Chain and Hooks. Pillow Blcx 
Babbitted Bearings; Ball and Roller B. 
ings; Clamp Couplings; Plate Couplings;' 
Flange Couplings; Tooth Clutches; Crab 
Couplings; Cone Clutches; Universal 
Joints; Crane Chain; Chain Friction; 
Crane Hooks; Drum Scores. 

No. 9. Springs, Slides and Machine 
Details. Formulas and Tables for Spring 
:lati<ms; Machine Machine 

Handles and -liars; Hand 

Wheels; Pin? Turn-buckles, 

etc. 

No. 10. Motor Drive, Speeds and Feeds, 
Taper Turning, and Boring 1 Bars. P< 
required for Cutting 

Speeds :iiid Feeds for Carbon and High- 
Machine Speeds and 

Feed iment of High -si 

St <<! Tools; Tap. f Turning; 
ing for 1 1 rs and Toi 

No. 11. Mining Machine Indexing, 
Clamping Devices and Planer Jacks. 

Tables for Milling Machine Indexing; 

Milling Spirals; An- 

for setting Indexing H Milling 

Clut' Clampiiu: 

and Clamps ; . 

No. 12. Pipe and Pipe Fittings. Pipr 
ron Fitth 

MACHINIST, tho monthly mechanical journal, originator of tin 1 Reference and 
Data Sheet Series, is published in four editions the Shop Edition, S1.00 a year; 
the EnrtinerriHii Edition, $2.00 a year; the Jtnllirni/ Edition. ?2.00 a year, and the 
Fwirin EdU- ; year. 

The Industrial Press, Publishers of MACHINERY, 
49-55 Lafayette Street, New York City, U. S. A. 



Bronz^ Fittings; Pipe Flanges; Pipe 
Bend.s; Pipe Clamps and Hangers; Dimen- 
siojns of Pipe for Various Services, etc. 

No. 13. Boilers and Chimneys. Fine 
Spacing and Bracing for Boilers; Strength 
or; Boiler Joints; Riveting; Toiler S-n 
Chimneys. 

No. 14. Locomotive and Railway Data. 
Locomotive Boilers; Bearing Pressures 
for Locomotive Journals; Locomotive 

sifications; Rail Sections; Fr< 
Switches and Cross-overs; Tires; Tractive 
Force; Inertia of Trains; l-Jiak-.- Lev< 
Brake Rods, etc. 

No. 15. Steam and Gas Fngines. Sat- 
urated Steam; Steam Pipe Sizes; Steam 
Engine Design; Volume of Cylinders; 
Stuffling Boxes; Setting Corliss Engine 
Valve Gears; Condenser and Air Pump 
Data; Hprsepower of Gasoline Engi 
Automobile Engine Crankshafts, etc. 

No. 16. Mathematical Talles. Squares 
of Mixed Numbers; Functions of 1- , 
tions; Circumference and Dii in 
Circles; Tables for Spacing off Cir- 
Solution of Triangles; Formulas 
ing Regular Polygons; Geometrical 
gression, etc. 

No. 17. Mechanics and Strength of Ma- 
terials. Work; Energy; Centrifugal 
Force Center of Gravity; Motion; 1 
tion; Pendulum; Falling Boc es; Strength 
of Materials; Strength of i^lat Plates; 
Ratio of Outside and JnsMe Radii 
Thick Cylinders, etc. 

No. 13. Beam Formulas and Structural 
Design. Beam Formulas; Sectional M 
uli o* Structural Shapes; J iam Charts: 
Areas of Structural 1 ugles: 1; 
ing; Splices for Channels and I- 
beams; Stresses in Roof Trusses, etc. 

No. 19. Belt, Rope and drain Drives. 
Dimensions <>r Pulleys: "\Y< ,_;hta of Pul- 
pwer of Belting; Belt Veloe- 
Angular Belt Drives; Horsep< 

e; Bending Stresses in Tire R"; 
kets for Link Chains; Formulas and 
'Lables fen- V )>rivint; 

Chain. 

No. 20. Wiring Diagrams, Heating and 

Ventilation, and Miscellaneous Tables. 

Typ r \Viring Diagrams; Resist- 

ance of Rffiflii' \Vire: Rubber Cov- 

urront T>ensiti-s for Vari- 

ntrifugal 

Pan and Blower ; H<H AN 

Capacities; Miscellaneous Tables: 
mal Equivalents, Metrir Conver 
Tables, Weights and Spoeiiie Cravii 
Metals, AVeights of Fillets, n 
entions,